"I suppose I've never questioned that the propensity to BE homosexual may in some cases be genetically determined. BUT by that same argument, the propensity to be an alcoholic may also be a genetic predisposition. HOWEVER in NEITHER case should society condone the expression of either predisposition. In other words, if engaging in homosexual sex is OK because the propensity is genetically predetermined then we MUST revoke drunk driving laws because alcoholism is also genetically predetermined." A rambling way to say simply that whatever the URGING we have to do things that are inappropriate, the behavior is STILL inappropriate.
You nail it.